Insulin can be kept at normal tempreture for a month as long as tempreture don't get too high or below freezing that is..
There is a but to this, you say that it was sent by courier, did they know that they were transporting insulin for you? As if not and it was sent by plane there is a very high possiblity it may have got frozen in flight! The baggag haul is only heated if they are carrying live stock, i.e dogs, cats etc.. So you need to consider this possiblity..